Switching mode power supply circuit

1. A switching mode power supply (SMPS) circuit, comprising: a first input rectification circuit, a first capacitor, a boost feedback control and driving unit, and at least one boost converter circuit, wherein: the boost converter circuit comprises: a second rectification circuit, a second capacitor and a boost circuit, wherein the boost circuit includes a first inductor, a first switching component and a first output rectification circuit; the first input rectification circuit rectifies an input voltage and forms, together with the first capacitor, a first loop for charging the first capacitor; the second input rectification circuit rectifies the input voltage and forms, together with the second capacitor, a second loop for charging the second capacitor; one terminal of the first capacitor, one terminal of the second capacitor and an output of the first input rectification circuit are coupled at a same polarity; when the first switching component is turned on, the first inductor, the second capacitor and the first switching component form a third loop in which a rectified input voltage on the second capacitor charges the first inductor; when the first switching component is turned off, the first inductor, the second capacitor, the first capacitor and the first output rectification circuit form a fourth loop in which an induced voltage on the first inductor is superimposed onto a voltage on the second capacitor to charge the first capacitor through the first output rectification circuit; the first capacitor supplies energy to a load; and the boost feedback control and driving unit outputs a chopping signal with a predetermined frequency and duty to turn on or turn off the first switching component.

2. The SMPS circuit according to claim 1 , further comprising an input inrush current limiting circuit which is arranged in the first loop, and does not belong to any one of the second loop, third loop and fourth loop.

3. The SMPS circuit according to claim 2 , wherein the input inrush current limiting circuit at least comprises a resistance or any combination of resistance, inductance and capacitance.

4. The SMPS circuit according to claim 1 , wherein the second input rectification circuit includes a second switching component, a third switching component and an input AC phase monitoring and rectification control unit; one terminal of the second switching component and one terminal of the third switching component are coupled to a node between the second capacitor and the first inductor, the other terminal of the second switching component and the other terminal of the third switching component are respectively coupled to two poles of an AC input; the input AC phase monitoring and rectification control unit controls a synchronous turn-on or turn-off of the second and third switching components according to a voltage or phase of the input AC.

5. The SMPS circuit according to claim 1 , wherein the first output rectification circuit is a fourth switching component; after a current of the fourth loop discharges a parasitic capacitor of the fourth switching component, the fourth switching component is controlled to turn on by the boost feedback control and driving unit in a zero voltage switching mode.

6. The SMPS circuit according to claim 5 , wherein the first inductor operates at a discontinuous mode; after a current in the first inductor returns to zero, a resonant current caused by a voltage on the first capacitor charging the second capacitor and first inductor, with the fourth switching component being turned off by the boost feedback control and driving unit, discharges a parasitic capacitor of the first switching component, allowing the first switching component to turn on next time in a zero voltage switching mode.

7. The SMPS circuit according to claim 6 , wherein the boost feedback control and driving unit is further configured to monitor a zero-return of the current in the first inductor; when the current in the first inductor is detected to have returned to zero, an instant current to discharge a parasitic capacitor of the first switching component is adjustable by controlling a time of turn-off of the fourth switching component, so as to control a speed and time interval of discharging of the parasitic capacitor of the first switching component, wherein during a dead time when the first and fourth switching components are both turned off, the parasitic capacitor of the first switching component is effectively discharged, allowing the first switching component to turn on next time at a substantial zero voltage state.

8. The SMPS circuit according to claim 5 , wherein the boost feedback control and driving unit is further configured to dynamically adjust a dead time of complement driving signal for the first switching component and the fourth switching component.

9. The SMPS circuit according to claim 1 , wherein the boost feedback control and driving unit is further configured to monitor both an instant input voltage and an output voltage of each boost converter circuit, and obtain, through logic or mathematic calculation, a maximum duty to ensure a sufficient magnetic reset of the first inductor, so as to limit a conducting time of the first switching component.

10. The SMPS circuit according to claim 1 , wherein two or more boost converter circuits are controlled by the boost feedback control and driving unit to operate in a synchronous or interleaved or phase-shift mode.